The present invention relates to plasma torches and, more particularly, to transferred type plasma-arc torches for use in welding and cutting of metals.
As is well-known, transferred type plasma torches have been widely used for welding and cutting metals. In such torches, it is essentially required that an electrode be centered in a tubular nozzle constricted at the tip to form a narrow passage, through which plasma forming gas is directed to the point to be cut or welded in the workpiece. If the electrode is not centered in the nozzle, it is difficult to produce a stabilized plasma arc, resulting in the failure of the function of the torch.
Many attempts have been made to center the electrode in the nozzle, with an error of not more than 0.1 mm. It is, however, very difficult to locate the electrode in the position prescribed even when using precisely worked parts for the torches. Because, the error in the relative position occurs between the nozzle and the electrode, the nozzle tip is mounted in the torch body by means of a jacket and an insulating adaptor, while the electrode is mounted in the body by means of a collet attachment.
It is therefore an object of the present invention to provide a transferred type plasma torch wherein an electrode can be located in the position prescribed with ease and, centered in a nozzle with high precision.
Another object of the present invention is to provide a transferred plasma torch wherein the displacement of the electrode due to the impacts applied on the torch can be prevented.
A further object of the present invention is to provide a transferred type plasma torch which can be manufactured at a moderate price.